Page Section: Left Content Column

Page Section: Centre Content Column

Diagnostic errors

In the area of patient safety, recent attention has
focused on diagnostic errors, including cognitive errors. Doctors
often have to make rapid decisions because they need to see many
patients in a limited time. To make correct decisions, doctors must
first gather information on which to base their judgement. The most
efficient way to do this is to ask the most appropriate questions,
interpret the answers properly and to stop searching further when
there is sufficient information to make a judgement. However,
unconscious cognitive biases may create pitfalls throughout this
process. One such bias is confirmation bias - a tendency to look
for, notice and remember information that fits in with the
pre-existing expectations. Information that contradicts those
expectations may unconsciously be ignored or dismissed as
unimportant. In taking medical histories, doctors sometimes
ask questions that solicit information confirming their earlier
judgements or they may stop asking questions because they reach an
early conclusion and so fail to unearth key data.

Confirmation bias can lead to treatment errors and so it is
important to remain constantly vigilant for information that might
contradict the existing diagnosis and give such information careful
consideration rather than dismissing it as irrelevant.

In a recent HDC decision 14HDC00919 (15 August 2016) a GP saw a
38-year-old man who was experiencing coughing fits, particularly at
night. The man was relatively fit but was overweight, a smoker and
had been diagnosed with diabetes. When the GP saw the man in
September and November 2013 he thought the man might have a chest
infection and prescribed antibiotics, which seemed effective, as
the man's symptoms disappeared for about six weeks.

The man returned to the GP and reported another coughing fit and
that he was coughing up blood and felt unwell. He reported bleeding
from his nose and shortness of breath. The GP ordered an urgent
chest x-ray and documented that the man might require specialist
work up. The x-ray revealed nothing of concern. Subsequently, the
GP noted that the man was still coughing and smoking and prescribed
further antibiotics and anti-smoking medication.

By January 2014 the man was experiencing shortness of breath and
further coughing fits, during which he would sometimes cough up
blood. The GP sent a semi-urgent referral to the DHB respiratory
service for a chest x-ray and stated the man might require
specialist work up.

Expert adviser Dr David Maplesden advised that until that stage,
the GP's actions were appropriate as the man's symptoms and
assessment findings were primarily respiratory in nature and there
had been positive response to antibiotic treatment.

Overnight on 7 February 2014, the man coughed all night and had
to sit up using his inhaler. He returned to the GP who recorded
that the man needed an urgent respiratory appointment but did not
advise the DHB that the referral was now urgent. There is no record
that the GP carried out a physical examination although blood tests
were ordered.

On 14 February 2014 the man returned to the GP with bowel
issues. The GP sent a further referral to the DHB for specialist
gastroenterology review. Three days later the DHB informed the GP
that an appointment had been booked for the man for 1 May 2014 at
"the medical clinic". The GP assumed this related to the
respiratory appointment but in fact it was for the gastroenterology
review. Although the Commissioner accepted that this was a
reasonable assumption to make, he considered that the GP should
have attempted to expedite the respiratory appointment. However,
the GP appeared unaware that he was able to take steps to bring
forward specialist appointments.

There are no physical assessments documented for any
consultations after 28 January 2014. By mid February the man's
symptoms had changed to include weight loss, anorexia and fatigue.
On 25 February the GP prescribed an antibiotic without examining
the man. Sadly, overnight on 25/26 February 2014, the man's
condition deteriorated, he collapsed and died. His cause of death
was respiratory failure due to a severe pulmonary oedema and
pleural effusions. He was found to have had severe coronary artery
disease, signs of an old myocardial infarction and an enlarged
liver.

The GP stated that he never considered that the man's issues
might be heart related. Dr Maplesden advised that there was no
particular reason to suspect that someone in the man's age group
with no symptom history suggestive of cardiac ischaemia could have
severe ischaemic heart disease, including a previous myocardial
infarction. Dr Maplesden noted that the predominant symptoms of a
cough and dyspnoea were consistent with a diagnosis of COPD or
perhaps adult onset asthma. However, by mid February 2014 the rapid
progression of the man's symptoms and increasing symptoms of weight
loss, anorexia and fatigue were less typical for COPD in a
relatively young person. Dr Maplesden advised that further
investigation was required, with a careful and thorough
reassessment by the GP, including a physical examination.

It was held that the GP failed to advocate appropriately for the
man by failing to follow up the respiratory referral or inform the
DHB when the man's condition deteriorated, and failed to carry out
the appropriate physical assessments of the man before prescribing
an antibiotic. Accordingly, the GP failed to provide services with
reasonable care and skill and breached Right 4(1) of the Code.
There was also found to be a pattern of inadequate documentation in
the GP's referral letter and clinical notes and so the GP also
breached Right 4(2). Adverse comment was made about the DHB's
communication with the GP.

It is important to be alert to changes in presentation that
could indicate a reassessment of the differential diagnosis is
required. In addition, when making referrals, GPs should act as
advocates for their patients, by reporting changes in the patients'
condition and when necessary, requesting more timely
appointments.